Technical Articles

Operating on the Low Bands–160 and 80 Meters

There are very good reasons why you should use the 160 and 80 meter bands. They are usually the least likely to fail under adverse propagation conditions. In times of regional disasters when a repeater is down, they can provide a reliable alternative. And both are suitable for NVIS (Near Vertical Incidence Skywave) mode propagation for local contacts.

These bands provide the best coverage at nighttime. Signals on 160 and 80 meters make fairly rapid transitions around dawn and dusk. Signals between stations operating on 160 and 80 meters often exhibit a peak in signal strength when the easternmost stations are close to sunrise–this is known as the dawn enhancement. It’s a good time for stations to be on the air and take advantage of the stronger signals and chase DX.

160 Meters

In the early days of radio, it was believed that anything above 200 meters was unusable, so amateurs were allowed to experiment with the leftover frequencies nobody wanted. Amateurs began with frequency allocations from 200 meters to 150 meters (1.5 MHz to 2 MHz). To accommodate the growing number of AM broadcast stations and other services, the 160 meter band was eventually changed to 1.8 to 2.0 MHz.

Known as “top band,” 160 meters is usually considered part of the HF bands and is the lowest frequency band commonly in use by amateurs, though it’s technically an MF (medium frequency) band. Most modern HF radios cover 160 meters, providing hams with an introduction to the band.

It’s also known as “The Gentleman’s Band” for a good reason. The QSOs are casual and people generally treat each other with respect. If you want to hear what amateur radio was like years ago, give it a try. You’ll experience less crowding and better manners.

The primary reason you won’t hear much traffic on 160 meters is due to antenna requirements. A 160 meter vertical is huge at 123 feet tall; an inverted V or dipole is massive at 246 feet long. Not all amateurs have enough real estate to accommodate them. But there’s good news–you can fit a full-sized 160 meter antenna in a small 100 x 60 foot lot without loading coils or complicated matching systems. An inverted L is a solution that has a relatively small footprint and works well with a few radials. Also, DX Engineering’s 160 Meter Thunderbolt Vertical Antenna, which comes with a custom-designed capacity hat system, checks in at only 55 feet.

At night, when the D-layer in the ionosphere disappears, communication distances increase and it may be possible to hear stations several hundred or more miles away. Grey line, the area where night and day meet, is important to propagation on 160 meters. Grey line is also known as the terminator. Stations in this grey line zone have an increased chance of making long-distance QSOs, especially if the other station is also in a grey line zone. Ducting, where the signal propagates along the ionosphere rather than repeated hops between ground and the F-layer, appears to be another contributor to long-distance propagation on 160 meters.

The 160 meter band utilizes lower sideband (LSB) for voice and includes all the other popular modes like CW and digital (see Table 1 at end of aticle). It’s a regional band with good ground wave coverage for nearby contacts, but under the right conditions it can open up. If you’re only interested in local QSOs (rag-chewing, nets, etc.), then 160 meters is good just about anytime. If you want to work DX on 160 meters, some persistence, time, and effort are required. An amplifier also helps.

Unlike the higher HF bands, long-distance propagation for this band is often better around sunspot minimum when solar activity is low and noise levels are lower. As a general rule, the probability of long-distance contacts improves in winter because of the longer hours of darkness and lower levels of static. December through March is prime time for this band. It’s also when the 160 meter contests are scheduled.

80 Meters

Because 160 meters is relatively close in frequency to 80 meters, you would assume the two would have very similar propagation characteristics. But there are some significant differences in coverage.

During the day, stations up to a few hundred miles away can be heard, making 80 meters a better choice for medium-distance contacts than 160. At night, you can pull in ham radio stations from distances of 1,000 miles or more. Greater distances can be achieved with good antennas and higher transmitting power. The 80 meter band opens up during the years of the sunspot minimum, but it can perform well at anytime.

The 80 meter band has numerous evening nets operating on LSB. It’s also very popular for rag-chewing. If chatting with other hams in the evening for an hour or two interests you, check out 80 meters. However, be aware that you’ll sometimes run across some loose cannons and LIDS (rude operators)–it’s best to avoid them.

There’s plenty of room for other modes, given that the total amount of spectrum space is more than double that of 160 meters at 500 KHz. You’ll find digital, CW, RTTY, SSTV, and AM (see Table 1). With dipole antenna sizes around 125 feet in length, this is often the lowest band on which many amateurs choose to operate.

As far as 80 meter propagation along the grey line, you can achieve good results when contacting stations from the other side of the globe, with signal strengths rivaling those of many local stations. However, this can be short-lived and selective in terms of location. Grey line propagation tends to be best during spring and autumn on 80 meters.

QRN: Good News/Bad News

In general, 160 and 80 meters are best at night–a viable alternative to other HF frequencies 15 meters and above following sunset. However, they sometimes suffer from interference.

There are two sources of noise that make receiving difficult: man-made and atmospheric. The primary problem is thunderstorm activity, which can make copying signals a challenge. Lightning creates radio noise that is reflected off the ionosphere just like regular radio signals. However, the good news is thunderstorm activity drops off during the winter, allowing good 160 and 80 meter operating conditions.

The combination of day/night, summer/winter, and sunspot cycle variations keeps HF operation on 160 and 80 meters interesting. You may be surprised at what you’ll find when you tune across these bands.

Table 1–ARRL Band Plan: Where and what is on the bands.

160 Meters (1.8-2.0 MHz) 

1.800 – 2.000: CW

1.800 – 1.810: Digital Modes

1.810: CW QRP

1.843-2.000: SSB, SSTV and other wideband modes

1.910: SSB QRP

1.995 – 2.000: Experimental

1.999 – 2.000: Beacons

80 Meters (3.5-4.0 MHz)  

3.590: RTTY/Data DX

3.570-3.600: RTTY/Data

3.790-3.800: DX window

3.845: SSTV

3.885: AM calling frequency

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